Heat dissipation device

ABSTRACT

A heat dissipation device adapted for dissipating heat generated by a heat source is provided. The heat dissipation device includes a base and a heat dissipation fin assembly. The base is disposed on the heat source. The heat dissipation fin assembly is disposed on the base and includes a plurality of parallel fins. The heat dissipation fins assembly has opposite air inlet side and air outlet side. A turbulence generating structure is formed by at least a part of the fins or holes at the air inlet or the air outlet of the heat dissipation fin assembly.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan application serial no. 98103668, filed on Feb. 5, 2009. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of specification.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a heat dissipation device, and more particularly to a heat dissipation device which includes heat dissipation fins designed to generate a desired heat dissipation airflow field.

2. Description of Related Art

In general, a motherboard inside a computer host includes a plurality of electronic components mounted thereon. A part of the electronic components such as a central processing unit (CPU), a pulse width modulator (PWM) and a north bridge generate a considerable amount of heat during operation. If the heat cannot be timely removed such that the heat is continuously accumulated on the electronic components, the temperature of the electronic components will gradually rise and exceed their normal operating temperature. As a result, the electronic components cannot operate stably, thereby causing a crash of the computer host. In addition, if the temperature is unduly high, the electronic components may be damaged, thus causing a permanent failure.

A conventional heat dissipation device generally includes a heat dissipation base, a fan, fins, and an airflow guide plate. As the fan operates, the airflow generated by the fan can enter the heat dissipation base via an air inlet of the heat dissipation base and escape through an air outlet of the heat dissipation base to dissipate the heat of the electronic components. In addition, the airflow guide plate disposed below the fins can guide a portion of the airflow toward a surface of the circuit board to dissipate the heat of the electronic components around the heat dissipation base.

However, in this heat dissipation device, the airflow generated by the fan must be guided by the airflow guide plate coupled to the heat dissipation base to dissipate the heat of the electronic components on the surface of the circuit board. Therefore, the design of the heat dissipation device may be complicated. Furthermore, extra components are required to assemble the heat dissipation base and the airflow guide plate, which not only increases the manufacturing cost of the heat dissipation device, but also reduces the reliability of the heat dissipation device due to the manufacturing tolerance or assembly tolerance.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a heat dissipation device which can generate a desired cooling airflow field to provide an improved performance of dissipating the heat of a heat source.

The present invention provides a heat dissipation device adapted for dissipating heat of a heat source. The heat dissipation device includes a base and a heat dissipation fin assembly. The base is adapted to be disposed on the heat source. The heat dissipation fin assembly is disposed on the base and includes a plurality of fins. The heat dissipation fin assembly has opposite air inlet side and air outlet side. A turbulence generating structure is formed by at least a part of the fins or holes at the air inlet side or the air outlet side.

According to one embodiment of the present invention, the fins or holes are disposed on one side of a centerline of the heat, dissipation fin assembly, and the number of the fins or holes gradually increases in the direction toward or away from the heat source.

According to one embodiment of the present invention, the turbulence generating structure is formed by reducing the size of at least a part of the fins at the air outlet side.

According to one embodiment of the present invention, the turbulence generating structure comprises a plurality of projections or recesses on surfaces of the fins.

According to one embodiment of the present invention, the turbulence generating structure is formed by downwardly bending at least a part of the fins at the air outlet side.

According to one embodiment of the present invention, the fins or holes for forming the turbulence generating structure are disposed below a middle height line of the heat dissipation fin assembly and are uniformly distributed.

According to one embodiment of the present invention, the turbulence generating structure comprises a plurality of projections or recesses on surfaces of the fins.

According to one embodiment of the present invention, the turbulence generating structure is formed by downwardly bending at least a part of the fins at the air outlet side.

In view of the foregoing, the turbulence generating structures can redirect the airflow flowing through the heat dissipation device, thereby cooling the heat sources below the heat dissipation device and at the air outlet side. In addition, the turbulence generating structures can increase the longitudinal turbulence intensity of the airflow at the air outlet/inlet sides and change the longitudinal press gradient of the airflow, thus improving the cooling performance of the heat dissipation device.

In order to make the aforementioned and other features and advantages of the present invention more comprehensible, embodiments accompanied with figures are described in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates one embodiment of the heat dissipation device disposed on a circuit board.

FIG. 2 is a top view of the heat dissipation device disposed on the circuit board of FIG. 1.

FIG. 3 illustrates one embodiment of the heat dissipation fin assembly disposed on the circuit board.

FIG. 4 illustrates a profile of the airflow field at the air outlet side of the heat dissipation fin assembly of FIG. 3.

FIG. 5 illustrates an alternative embodiment of a heat dissipation fin assembly disposed on a circuit board.

FIG. 6 illustrates a profile of the airflow field at the air outlet side of the heat dissipation fin assembly of FIG. 5.

FIG. 7 illustrates another embodiment of a heat dissipation fin assembly disposed on a circuit board.

FIG. 8 illustrates another embodiment of a heat dissipation fin assembly disposed on a circuit board.

FIG. 9 illustrates still another embodiment of a heat dissipation fin assembly disposed on a circuit board.

DESCRIPTION OF THE EMBODIMENTS

FIG. 1 illustrates one embodiment of the heat dissipation device disposed on a circuit board. FIG. 2 is a top view of the heat dissipation device disposed on the circuit board of FIG. 1. Referring to FIGS. 1 and 2, the heat dissipation device 100 includes a base 110, a heat dissipation fin assembly 120, and a fan 130. The base 110 is disposed on the circuit board 10 over a heat source 190. In the present embodiment, for example, the circuit board 10 may be a motherboard and the heat source 190 may be a central processing unit (CPU).

The heat dissipation fin assembly 120 is disposed on the base 110 and includes a plurality of parallel fins 120 a. The heat dissipation fin assembly 120 has an air inlet side 122 and an air outlet side 124 opposite to the air inlet side 122. The fan 130 is disposed at the air inlet side 122. As the fan 130 rotates, the fan 130 drives an airflow to enter the heat dissipation fin assembly 120 from the air inlet side 122 and escape the heat dissipation fin assembly 120 through the air outlet side 124. In addition, in the present embodiment, a turbulence generating structure 126 is formed at the air outlet side 124 of the heat dissipation fin assembly 120 in order to control a field of the airflow through the heat dissipation fin assembly 120. Therefore, when the airflow flows through-the air outlet side 124 of the heat dissipation fin assembly 120, it flows through the turbulence generating structure 126 at the same time.

FIG. 3 illustrates one embodiment of the heat dissipation fin assembly disposed on the circuit board. FIG. 4 illustrates a profile of the airflow field at the air outlet side of the heat dissipation fin assembly of FIG. 3. Referring to FIGS. 3 and 4, the turbulence generating structure 226 is formed on a part of the fins 220 a at the air outlet side 224. In the present embodiment, a part of the fins 220 a have the same configuration, and the rest of the fins 220 a form the turbulence generating structure 226. More specifically, in the present embodiment, the turbulence generating structure 226 is formed by reducing the size of the part of the fins 220 a at the air outlet side 224. The turbulent generating structure 226 can change a longitudinal turbulence intensity as well as a longitudinal pressure gradient of the airflow at the air outlet side. Thus, the airflow flowing through the turbulence generating structure can be disturbed to form the airflow field profile shown in FIG. 4.

In addition, in the present embodiment, the fins 220 a used for forming the turbulence generating structure 226 are disposed adjacent the circuit board 20 and have their size gradually decreased in the direction toward the circuit board 20. As such, when the airflow leaves the heat dissipation fin assembly 220 through the air outlet side 224, a higher longitudinal turbulence intensity can be formed at the air outlet side 224 and the longitudinal press gradient can be changed under the influence of the turbulence generating structure 226. As a result, the airflow can be guided toward the surface of the circuit board 20, thereby effectively dissipating the heat of the heat source 290 on the circuit board 20 and other components around the heat source 290.

FIG. 5 illustrates an alternative embodiment of a heat dissipation fin assembly disposed on a circuit board. FIG. 6 illustrates a profile of the airflow field at the air outlet side of the heat dissipation fin assembly of FIG. 5. Referring to FIGS. 5 and 6, the heat dissipation fin assembly 320 of the present embodiment includes a turbulence generating structure 326 formed on a part of the fins 320 a at the air outlet side 224. More specifically, the turbulence generating structure 326 includes a plurality of holes through the surfaces of the fins 320 a. In the present embodiment, the holes 326 a are formed, for example, by stamping the fins 320 a, and the number of the holes 326 a in each fin gradually increases in the direction toward the circuit board 30.

As such, the airflow flows through the holes 326 a before escaping the heat dissipation fin assembly 320 through the air outlet side 324, and then flows toward the surface of the circuit board 30. The turbulence generating structure 326 can redirect the airflow, increase the longitudinal turbulence intensity as well as change the longitudinal press gradient, thereby improving the heat dissipation performance of the heat dissipation fin assembly 320.

FIG. 7 illustrates another embodiment of a heat dissipation fin assembly disposed on a circuit board. Referring to FIG. 7, the heat dissipation fin assembly 420 of the present embodiment is different from the above-described heat dissipation fin assembly 320 in that the holes 426 a are disposed at one side of a centerline of the heat dissipation fin assembly 420 and the number of the holes 426 a in each fin gradually decreases in the direction toward the circuit board 40. In other words, in the present embodiment, the holes 426 a are disposed at one side of the centerline of the heat dissipation fin assembly 420 and the number of the holes 426 in each fin gradually increases along the direction away from the heat source 490.

FIG. 8 illustrates another embodiment of a heat dissipation fin assembly disposed on a circuit board. Referring to FIG. 8, the heat dissipation fin assembly 520 of the present embodiment is different from the above-described heat dissipation fin assembly 420 in that the holes 526 a are disposed at one side of a centerline of the heat dissipation fin assembly 520 and the number of the holes 526 a in each fin maintains the same in the direction toward the circuit board 50.

FIG. 9 illustrates still another embodiment of a heat dissipation fin assembly disposed on a circuit board. Referring to FIG. 9, the heat dissipation fin assembly 620 of the present embodiment is different from the above-described heat dissipation fin assembly 320 in that the turbulence generating structure 626 includes a plurality of bending portions 626 a on the surface of the fins 620 a. In the present embodiment, the bending portions 626 a are formed by and downwardly bending at least a part of the fins 620 a at the air outlet side, such as by stamping portions of the fins downwardly, and the number of the bending portions on each fin gradually decreases in the direction toward the circuit board 60. In an alternative embodiment, these bending portions 626 a can also be replaced with projections.

The foregoing embodiments describe various turbulence generating structures that are formed by changing the size of the fins or forming projections on the fins or holes in the fins. However, these embodiments should not be used to limit the scope of the present invention. It should be noted that location and distribution of the turbulence generating structures on the fins, and the number and shape of the turbulence generating structures can be varied to meet actual requirements.

As to the location of the turbulence generating structures on the fins, the turbulence generating structure are only formed on a part of the fins and in locations adjacent the motherboard in the foregoing embodiments. It should be understood, however, that the turbulence generating structure can be formed on all fins or fins in other positions without departing the spirit and scope of the present invention.

As to the projections on or the holes in the fins that are used to form the turbulence generating structures, the number, shape or distribution of the projections or holes can be varied according to actual requirements. More specifically, the number or size of the projections or holes is not limited to any particular embodiments described herein, and the holes can also be replaced with recesses. In addition, different than the above-described distribution of the projections or holes that the number of the projections or holes gradually decreases or increases in the direction toward the motherboard, the projections or holes can be distributed in another manner according to actual requirements of the airflow field.

In summary, the turbulence generating structures can redirect the airflow flowing through the heat dissipation device, thereby cooling the heat sources below the heat dissipation device and at the air outlet side. In addition, the turbulence generating structures can increase the longitudinal turbulence intensity and change the longitudinal press gradient of the airflow at the air outlet side, thus improving the cooling performance of the heat dissipation device. The heat dissipation device of the present invention can eliminate the guide plate, thereby reducing the manufacturing cost. At the same time, because the guide plate is not needed, the design of the heat dissipation device can be simplified and the heat dissipation device can thus have an improved reliability.

It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents. 

1. A heat dissipation device adapted for dissipating heat of a heat source, the heat dissipation device comprising: a base adapted to be disposed on the heat source; and a heat dissipation fin assembly disposed on the base and comprising a plurality of fins, the heat dissipation fin assembly having opposite air inlet side and air outlet side, wherein a turbulence generating structure is formed by at least a part of the fins or holes at the air inlet side or the air outlet side.
 2. The heat dissipation device according to claim 1, wherein the fins or holes are disposed on one side of a centerline of the heat dissipation fin assembly, and the number of the fins or holes gradually increases in the direction toward or away from the heat source.
 3. The heat dissipation device according to claim 1, wherein the turbulence generating structure is formed by reducing the size of at least a part of the fins at the air outlet side.
 4. The heat dissipation device according to claim 1, wherein the turbulence generating structure comprises a plurality of projections or recesses on surfaces of the fins.
 5. The heat dissipation device according to claim 1, wherein the turbulence generating structure is formed by downwardly bending at least a part of the fins at the air outlet side.
 6. The heat dissipation device according to claim 1, wherein the fins or holes for forming the turbulence generating structure are disposed below a middle height line of the heat dissipation fin assembly and are uniformly distributed.
 7. The heat dissipation device according to claim 6, wherein the turbulence generating structure comprises a plurality of projections or recesses on surfaces of the fins.
 8. The heat dissipation device according to claim 6, wherein the turbulence generating structure is formed by downwardly bending at least a part of the fins at the air outlet side. 